Billionaire Jim Simon’s $15 billion hedge fund firm has been cheating New York out of much-needed unemployment insurance payments, according to a recent ruling by the state’s Unemployment Insurance Appeals Board.

Renaissance Technologies has 20 days to appeal.

The Labor Department has been battling RenTech since 2009 over its practice of classifying security guards as contractors, which allowed the firm to pay a lower rate of unemployment benefits.

The state will now review employment records to determine how much the secretive trading firm owes in back taxes and penalties, sources said.

David Wims, lawyer for Louis Marsicovetere, a former RenTech security guard at the center of the dispute, said he expects RenTech to appeal.

“I don’t think the appeal will be successful but I expect them to do it.”

Marsicovetere called the decision “fair and righteous” and RenTech declined to comment.

The guards were instructed to shred confidential documents and walk about the firm’s floors “so that Renaissance employees would feel more secure,” the ruling said.